1. The Field of the Invention
The present invention relates to apparatus for removing magnetic particles from a fluid. The apparatus finds particular application in the oil and gas industry in relation to separating iron-containing swarf from free-flowing or viscous liquid mud.
2. The Relevant Technology
Oil and gas wells usually have their bore holes lined with steel pipes, referred to normally as casing. In mature wells, when oil or gas production drops below economic production levels, it is often useful to utilise at least part of said bore hole. In order to be able to do this one alternative is to remove the casing completely. However, it is more cost effective to simply drill the pipeline out, or at least to drill a window in the pipeline. The window can then be used to allow a drilling assembly to exit the bore hole and reach a new part of the reservoir.
Such a method obviously produces large quantities of steel swarf derived primarily from the pipeline. The swarf is mixed during the drilling process with large quantities of mud either from the bore hole or from its introduction as a lubricant. Typically the mud/swarf mixture will comprise a sufficient quantity of water to enable the mixture to flow. Due to the high steel content of the mud when it exits the bore hole and its potential hazard, in part due to the sharpness of the metal slithers it contains, disposal or re-use of the mud can be problematic. One method of decontamination is simply to remove excess water from the mixture and then separate the larger swarf pieces by hand. This is obviously a time consuming and potentially dangerous mode of separation.
It is an object of the present invention to provide an improved apparatus to separate the solid magnetic or magnatisable particles from a fluid system and in particular, apparatus which can be applied in the oil and gas industry.